This is an absolutely critical thing for us to resolve in some way or another for 20.04.
tl;dr, if there's an existing partition scheme, the Erase Disk option will fail trying to create the new partition table. See Launchpad bug.
If we have to, we may be able to work around this with a shellprocess
doing one of two things after somehow detecting that Erase Disk has been chosen: Temporarily moving/renaming os-prober after the partition selection and reverting it at the end.
- Arguably more dangerous and would require us knowing the target device: checking for an existing partition table and removing it before the installation process starts.
Hopefully upstream gets to it first.